Northumberland County was established in 1772 as the tenth county of Pennsylvania. It is called the “Mother of Counties,” with 29 counties split from it over the years. Northumberland County encompassed as much as 15,000 square miles at its height. Today, it covers 470 square miles of the Susquehanna Valley. The county seat, Sunbury, was also created in 1772, while Shamokin sprouted from the increase in commerce and business in the 1830s.
Industry is intertwined with Northumberland’s history. Anthracite coal was the original natural resource in the early 1800s, used to produce iron. Other profitable industries like silk, dairy, and dress factories soon followed. Coal mining and silk production waned with the Great Depression, to be replaced by oil drilling and synthetic textiles.
Pick Your Adventure in Northumberland County, spend a day at Knoebels Amusement Park, or do your research with the Susquehanna River Valley Visitors Bureau.
As of 2026 the population of Northumberland County is 90,409. The population is expected to shrink to 89,736 by 2031 - a growth rate of -0.15%.
The median age of Northumberland County residents is 45.
The diversity index of Northumberland County is 29.0, meaning that there is a 29% chance that any two people selected out of 100 residents will be of different race or ethnicity from one another.
The average household income in Northumberland County is $85,805 and projected to be $98,601 in 2031. Per capita income is $35,935, projected to be $41,240 in 2031. 2.66% of households – 2,402 – have an income of $200,000 or higher. Average net worth is $845,686 and the average disposable income is $66,933.
There are 43,218 housing units in Northumberland County; 27,297 are owner-occupied, 10,228 are rented, and 5,693 are vacant. The average home value is $247,426, with 1,241 homes built in 2010 or later, and 16,526 built in 1939 or earlier.
There are 2,797 businesses in Northumberland County, employing 32,534 workers and pulling from a labor force of 40,250 age 16 and above. 17,921 workers commute into Northumberland County from outside the county or state. Key industries for the area include:
22,172 residents both live and work in/around Northumberland County. The average travel time is 25.2 minutes. 9.28% people have a commute of less than 5 minutes while 5.05% commute 90 minutes or more each way. Of commuters, 30,708 drive alone, 3,640 carpool, and 70 take public transportation. 1,813 use other modes of transport such as motorcycle, bicycle, walking, etc. 4,000 residents work from home.
31,160 members of the workforce hold a high school diploma or GED. 6,689 have associates degrees, 9,551 have bachelor’s degrees, and 4,339 hold a graduate or professional degree.
Source: ESRI, 2026-08-31
